Wellbore milling system

Abstract

The present invention, in one aspect, discloses a system for selectively anchoring a wellbore tool at a desired location in a wellbore or tubular member such as casing or tubing; such a system with a selectively settable anchor assembly that has a piston that is moved upwardly by fluid under pressure from the surface thereby moving one or more movable slips out from a body of the anchor assembly to set the anchor assembly in place; and such a system with a whipstock connected to the anchor assembly. Fluid under pressure pumped from the surface down a workstring to which the system is connected flows to the anchor assembly through or adjacent the whipstock. In one aspect a mill (or mills) is releasably connected to the whipstock. In one aspect, fluid under pressure flows through or adjacent the mill(s) to the whipstock. In one aspect a selectively actuable valve assembly is provided for selectively controlling the flow of fluid under pressure from an inlet end of the valve assembly out through an outlet end thereof for flow, e.g., to a mill, whipstock and/or anchor assembly. In one aspect such a valve assembly is used with a system as previously described to selectively provide actuating fluid under pressure to an anchor assembly as described to set the movable slip(s) thereof and, in one aspect, to then provide jetting fluid to jetting ports of the mill(s) upon release of the mill(s) from a whipstock.

What is claimed is: 
     
       1. A valve assembly for selectively controlling fluid flow through a hollow tubular in a string of hollow tubulars in a wellbore extending from a surface of the earth into the earth, the valve assembly comprising a hollow body with a hollow piston mounted for reciprocal up and down rotative movement therein, the hollow body having an inwardly projecting lug,   the hollow piston having at least one piston fluid flow port therethrough and the hollow body having at least two body fluid flow ports therethrough,   a ratchet sleeve connected to the piston, the ratchet sleeve having a branched slot therearound which is movable on the lug so that the ratchet sleeve and the piston are movable to a plurality of positions, the branched slot with a plurality of position recesses, at least one position in which fluid is flowable from within the hollow body to an exterior thereof and at least one position in which fluid is flowable from outside the hollow body thereinto.   
     
     
       2. The valve assembly of claim 1 further comprising the hollow body with a top and a bottom and a valve bore therethrough from top to bottom, the valve body having at least one valve flow port that allows the valve bore to communicate with an exterior of the hollow body,   the hollow piston movably and sealingly mounted in the valve bore, the hollow piston having a piston body with a top and a bottom and a piston bore extending therethrough from top to bottom, the hollow piston having at least one piston flow port that allows the valve bore to communicate with the at least one valve flow port so fluid is flowable through the piston, through the at least one piston flow port, and through the at least one valve flow port to the exterior of the hollow body,   the hollow body movable so that the branched slot is selectively movable on the lug and so that the valve assembly is selectively movable to any of a series of positions corresponding to the position recesses and to positions of the at least one valve flow port and the at least one piston flow port,   a spring abutting a bottom of the ratchet sleeve and an inner surface of a bottom of the valve flow bore,   the spring urging the ratchet sleeve and hollow piston upwardly and thereby releasably maintaining the lug in one of the plurality of position recesses,   the at least one valve flow port including at least one first valve flow port through the hollow body, and at least one second valve flow port through the hollow body, the at least one second valve flow port disposed below the at least one first valve flow port, and wherein the hollow body has a body channel therethrough with a top end disposed above the at least one second valve port and a bottom end disposed at a level of the lug, and wherein the mill apparatus has a fluid flow bore therethrough and at least one jet port therethrough,   the plurality of position recesses including recesses corresponding to   a fill position of the system in which the at least one first valve flow port and the at least one piston flow port are aligned so that as the system is run into the wellbore fluid in the wellbore is permitted to fill the system,   a circulate position of the system wherein the at least one piston flow port is aligned with the at least one second valve flow port so that fluid in the piston pumped down from the surface is flowable out from the hollow body,   a set anchor position of the system in which the at least one piston flow port is aligned with the top end of the body channel so that fluid pumped from the surface is flowable past the ratchet sleeve in a channel within the hollow body and out from the hollow body to the anchor assembly to set the anchor assembly, and   a mill position of the system in which fluid under pressure is pumpable through the valve assembly to the mill apparatus to exit the mill apparatus through the at least one jet port,   a plug extension connected to the bottom of the hollow piston, the plug extension having a top and a bottom and a plug fluid flow bore therethrough from top to bottom, the bottom of the plug extension projecting out from the bottom of the hollow body,   a plug releasably secured in the plug extension by a shearable member, and   the shearable member shearable to release the plug in response to fluid pumped from the surface to the valve assembly, such fluid passing through the hollow piston and through the plug extension, thereby opening the plug fluid flow bore to fluid flow and releasing pressure of fluid on the anchor assembly, and   the plug extension projecting into the milling apparatus and the milling apparatus having a bore for receiving the plug upon its separation from the plug extension, the bore disposed so that the plug does not block fluid flow to the at least one jet port.   
     
     
       3. The mill system of claim 2 wherein the branched slot extends around the entire ratchet sleeve for cycling of the valve assembly. 
     
     
       4. A milling system for milling an opening in a tubular in a tubular string in a wellbore extending down from a surface of the earth, the milling system comprising an anchor assembly comprising a body, a slip movably mounted to the body, the body having a fluid flow bore therethrough, the fluid flow bore having an enlarged cavity and a bottom cavity, a piston movably mounted in the fluid flow bore, the piston having a top and a bottom and with a piston flow bore therethrough from top to bottom through which fluid from the surface is flowable through the piston into the bottom cavity to force the piston upwardly in the enlarged cavity to move the slip from the body to set the anchor assembly in the tubular,   a whipstock connected to the anchor assembly,   a mill apparatus releasably connected to the whipstock,   a valve assembly connected at a top end thereof to the tubular string and at a bottom end thereof to the mill apparatus for selectively controlling fluid flow from the surface to the anchor assembly, and   the anchor assembly further comprising a hollow stem extending from an end of the fluid flow bore of the body of the anchor at a top of the enlarged cavity to a top of the piston so that fluid from the surface is flowable through the fluid flow bore of the body of the anchor, through the hollow stem into the piston flow bore, the hollow stem preventing fluid from flowing into the enlarged cavity above the piston, and the hollow stem movable up into the fluid flow bore of the body of the anchor as the piston moves upwardly in the enlarged cavity.   
     
     
       5. A milling system for milling an opening in a tubular in a tubular string in a wellbore extending down from a surface of the earth, the milling system comprising an anchor assembly comprising a body, a slip movably mounted to the body, the body having a fluid flow bore therethrough, the fluid flow bore having an enlarged cavity and a bottom cavity, a piston movably mounted in the fluid flow bore, the piston having a top and a bottom and with a piston flow bore therethrough from top to bottom through which fluid from the surface is flowable through the piston into the bottom cavity to force the piston upwardly in the enlarged cavity to move the slip from the body to set the anchor assembly in the tubular,   a whipstock connected to the anchor assembly,   a mill apparatus releasably connected to the whipstock,   a valve assembly connected at a top end thereof to the tubular string and at a bottom end thereof to the mill apparatus for selectively controlling fluid flow from the surface to the anchor assembly, and   the anchor assembly further comprising a screw in the body with a portion projecting outwardly from the body to stop upward movement of the slip.   
     
     
       6. A milling system for milling an opening in a tubular in a tubular string in a wellbore extending down from a surface of the earth, the milling system comprising an anchor assembly comprising a body, a slip movably mounted to the body, the body having a fluid flow bore therethrough, the fluid flow bore having an enlarged cavity and a bottom cavity, a piston movably mounted in the fluid flow bore, the piston having a top and a bottom and with a piston flow bore therethrough from top to bottom through which fluid from the surface is flowable through the piston into the bottom cavity to force the piston upwardly in the enlarged cavity to move the slip from the body to set the anchor assembly in the tubular,   a whipstock connected to the anchor assembly,   a mill apparatus releasably connected to the whipstock,   a valve assembly connected at a top end thereof to the tubular string and at a bottom end thereof to the mill apparatus for selectively controlling fluid flow from the surface to the anchor assembly, and   the anchor assembly further comprising a spring with a top end and a bottom end disposed in the enlarged cavity with the top end abutting a lower surface of the top of the piston and the bottom abutting an inner surface of a bottom of the enlarged cavity so that the spring urges the piston upwardly and prevents downward piston movement thereby maintaining the slip in an extended position once it has been moved by the piston.   
     
     
       7. The milling system of claim 6 further comprising the anchor assembly further comprising   a shearable member initially holding the piston down, the shearable member shearable in response to force on the piston by fluid pumped from the surface into the bottom cavity, and   the shearable member initially holding the piston against force of the spring and preventing the spring from urging the piston upwardly.   
     
     
       8. A milling system for milling an opening in a tubular in a tubular string in a wellbore extending down from a surface of the earth, the milling system comprising an anchor assembly comprising a body, a slip movably mounted to the body, the body having a fluid flow bore therethrough, the fluid flow bore having an enlarged cavity and a bottom cavity, a piston movably mounted in the fluid flow bore, the piston having a top and a bottom and with a piston flow bore therethrough from top to bottom through which fluid from the surface is flowable through the piston into the bottom cavity to force the piston upwardly in the enlarged cavity to move the slip from the body to set the anchor assembly in the tubular,   a whipstock connected to the anchor assembly,   a mill apparatus releasably connected to the whipstock,   a valve assembly connected at a top end thereof to the tubular string and at a bottom end thereof to the mill apparatus for selectively controlling fluid flow from the surface to the anchor assembly, and   the valve assembly further comprising a hollow body with a top and a bottom and a valve bore therethrough from top to bottom, the valve body having at least one valve flow port that allows the valve bore to communicate with space exterior to the hollow body,   a valve piston sealingly and movably mounted in the valve bore, the valve piston having a piston body with a top and a bottom and a piston bore extending therethrough from top to bottom, the valve piston having at least one piston flow port that allows the valve bore to communicate with the at least one valve flow port so fluid is flowable through the piston, through the at least one piston flow port, and through the at least one valve flow port to the exterior of the hollow body,   a ratchet sleeve connected to the piston body and having a branched slot, the branched slot with a plurality of position recesses,   a lug projecting inwardly from an interior surface of the hollow body into the branched slot,   the hollow body movable with respect to the ratchet sleeve and rotatable with respect to the ratchet sleeve so that the branched slot is selectively movable on the lug to any of a series of positions corresponding to various positions of the at least one valve flow port and the at least one piston flow port.     
     
     
       9. The milling system of claim 8 further comprising the valve assembly further comprising   a spring abutting a bottom of the ratchet sleeve and an inner surface of a bottom of the valve flow bore, and   the spring urging the ratchet sleeve and valve piston upwardly and thereby releasably maintaining the lug in one of the plurality of position recesses.   
     
     
       10. The milling system of claim 8 wherein the at least one valve flow port includes at least one first valve flow port through the hollow body, and at least one second valve flow port through the hollow body, the at least one second valve flow port disposed below the at least one first valve flow port, and wherein the hollow body has a body channel therethrough with a top end disposed above the at least one second valve port and a bottom end disposed at a level of the lug, and wherein the mill apparatus has a fluid flow bore therethrough and at least one jet port therethrough, and the milling system further comprising the plurality of position recesses including recesses corresponding to   a fill position of the system in which the at least one first valve flow port and the at least one piston flow port are aligned so that as the system is run into the wellbore fluid in the wellbore is permitted to fill the system,   a circulate position of the system wherein the at least one piston flow port is aligned with the at least one second valve flow port so that fluid in the piston pumped down from the surface is flowable out from the hollow body,   a set anchor position of the system in which the at least one piston flow port is aligned with the top end of the body channel so that fluid pumped from the surface is flowable past the ratchet sleeve in a channel within the hollow body and out from the hollow body to the anchor assembly to set the anchor assembly, and   a mill position of the system in which fluid under pressure is pumpable through the valve assembly to the mill apparatus to exit the mill apparatus through the at least one jet port.   
     
     
       11. The milling system of claim 10 further comprising the valve assembly further comprising   a plug extension connected to the bottom of the piston, the plug extension having a top and a bottom and a plug fluid flow bore therethrough from top to bottom, the bottom of the plug extension projecting out from the bottom of the hollow body,   a plug releasably secured in the plug extension by a shearable member, and   the shearable member shearable to release the plug in response to fluid pumped from the surface to the valve assembly, such fluid passing through the piston and through the plug extension to shear the shearable member, thereby opening the plug fluid flow bore to fluid flow and releasing pressure of fluid on the anchor assembly.   
     
     
       12. The milling system of claim 11 wherein the plug extension projects into the milling apparatus and the milling apparatus has a bore for receiving the plug upon separation of the plug from the plug extension, the bore disposed so that the plug does not block fluid flow to the at least one jet port. 
     
     
       13. The milling system of claim 8 wherein the branched slot extends around the entire ratchet sleeve for cycling of the valve assembly.